Electric vehicles, also known as e-cars, EVs, or plug-in electric vehicles (PEVs), are becoming increasingly popular as non-renewable fuel resources diminish. However, the increasing popularity of electric vehicles will result in a strain on the existing power distribution infrastructure as a growing number of vehicles require charging.
Typical electric cars may require 10 to 18 kWh of charge per 100 km, (e.g. the GM EV1 uses nearly 11 kWh and the Tesla Roadster uses nearly 17.4 kW·h). Charging requirements will vary by electric vehicle, battery technology, battery size, and battery charge status (half full, 30% full, etc.). Charging stations, including charging stations installed at residential premises, must be capable of efficiently providing the required amount of electricity. The maximum amount of power that can be provided to an electric vehicle is regulated by standards. According to the current Society of Automotive Engineers standard, the maximum current that may be supplied to the vehicle's on-board charger with a branch circuit breaker rated at 40 A is 32 A (continuous) for international standard Level-2 AC energy (208-240 V, single phase). Therefore, maximum continuous input power is specified as 7.68 kW (240 V×32 A). However, the present invention is not limited by the standard for maximum current set forth by the Society of Automotive Engineers.
Referring to FIG. 1, a typical end-point electrical distribution system 100 delivers power to a residential charging station 140 from the neighborhood distribution pole 103. This pole 103 has a neighborhood step-down transformer 104 that steps down the utility medium voltage to dual 120 VAC single phase (also called 240 VAC split phase). This voltage is fed through a meter 115 into the residential load control center 116. The load control center 116 consists of branch circuit breakers and distributes the power supply within various areas of the residence 120. The load control center may further consist of a load control communication center 117. Alternatively, the load control communication center 117 may operate as a separate device electrically connected to the load control center 116. One of the branch circuits feeds the charging station 140 for the residence 120. One or more electric vehicle charger cables 147 are fixed to, mounted onto, or plugged into the sockets on the charging station 140, and the other end of the charger cable 147 is connected to the vehicle 150 during charging.
Accordingly, there is a need for a system and method that can manage the disbursement of power from a neighborhood transformer so as to increase the efficiency of electric vehicle charging at the residences without significantly altering the existing power distribution and residential infrastructures. Additionally, there is a need for collaborative vehicle charging that does not compromise the comfort and privacy of the neighborhood residents.